The embodiments described herein relate generally to medicament delivery devices, and more particularly to a medicament delivery device for mixing a medicament, priming a medicament container, and delivering the medicament into a body of a patient.
Exposure to certain substances, such as, for example, peanuts, shellfish, bee venom, certain drugs, toxins, and the like, can cause allergic reactions in some individuals. Such allergic reactions can, at times, lead to anaphylactic shock, which can cause a sharp drop in blood pressure, hives, and/or severe airway constriction. Accordingly, responding rapidly to mitigate the effects from such exposures can prevent injury and/or death. For example, in certain situations, an injection of epinephrine (i.e., adrenaline) can provide substantial and/or complete relief from the allergic reaction. In other situations, for example, an injection of an antidote to a toxin can greatly reduce and/or eliminate the harm potentially caused by the exposure. Similarly, an injection of glucagon can reduce and/or eliminate the harm potentially caused by reduced blood glucose levels in individuals who suffer from diabetes (e.g., a hypoglycemic emergency).
Because emergency medical facilities are not always available when an individual is suffering from a medical condition, some individuals carry an auto-injector, a rescue inhaler, or the like to rapidly self-administer a medicament in response to such medical conditions. Some known auto-injectors include a vial containing a liquid medicament and a spring loaded needle to automatically penetrate the user's skin and inject the medicament. The storage of certain medicaments in a liquid form, however, can result in a shorter shelf life and/or an unstable medicament. Accordingly, some known auto-injectors include a vial containing a first medicament that is separated from a second medicament. Such auto-injectors are often referred to as “wet/dry” auto-injectors, because one medicament is often a liquid (e.g., water or another diluent) and the other medicament can be substantially solid or dry (e.g., lyophilized glucagon powder). Lyophilization is also known as “freeze drying.” In use, the first medicament and the second medicament must be mixed prior to injection.
Some known wet/dry injectors, however, require that the user manually actuate a mixing mechanism prior to injection (e.g., by twisting a portion of the device to complete the mixing step). Such configurations can, however, result in incomplete mixing and/or an injection occurring without mixing. In addition, the operation of some known wet/dry delivery systems includes manually inserting the needle into the skin prior to activation and subsequent medicament delivery. The operation of such configurations may also include separately attaching a needle to prepare the device for injection, resulting in a delay in delivery of the medicament. Moreover, such configurations can be complicated, making them difficult for a user to operate during an emergency or by an individual without medical training.
Some known wet/dry injectors employ a single mechanism to automatically mix and inject the medicaments contained therein. Because the mixing operation is dependent on the injection operation in such configurations, however, the medicament can be injected prior to the completion of the mixing operation and/or prior to the injector being properly positioned for the injection operation.
Some known wet/dry injectors are configured such that a user can manually vent and/or purge a portion of air included in the medicament container (e.g., mixed with or a part of the glucagon powder). In some instances, such known injectors are generally oriented in a predetermined manner (e.g., with the needle end facing upward) during the mixing process and/or prior to injection to facilitate the venting process (also referred to as “priming”). Such injectors, however, lack a locking mechanism and/or a compliance mechanism to prevent initiation of the mixing process when the injector is not properly oriented. Moreover, known some injectors are not configured to prevent an injection event from occurring prior to mixing the medicament and/or otherwise venting or priming a portion of air in the medicament container. Therefore, in many known auto-injectors, the venting process can be performed incorrectly or incompletely.
Procedures for using some known medicament delivery devices, including medical injectors and inhalers, include rapidly moving (or shaking) the device to enhance the mixing or otherwise assist in preparing the dose for delivery. Such known devices, however, do not include any mechanism for providing feedback regarding whether the medicament has been properly shaken or mixed.
Thus, a need exists for improved medicament delivery devices to improve the procedures for mixing a medicament, priming a medicament container, and delivering the medicament. Specifically, a need exists for an improved auto-injector that can separately store two or more medicaments or medicament portions and that can mix the medicaments or medicament portions and vent excess air from the medicament container prior to injecting the medicament.